Effect of Doppler Shift frequency on the performance of 2x2 OSTBC-OFDM System

2017 ◽  
Author(s):  
Diana Hayder Hussein ◽  
Thuraya Mahmood Qaradaghi
Keyword(s):  
Doppler Shift ◽  
Ofdm System ◽  
Shift Frequency

Effect of Doppler Shift frequency on the performance of 2x2 OSTBC-OFDM System

2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Diana Hayder Hussein ◽  
Thuraya Mahmood Qaradaghi
Keyword(s):  
Doppler Shift ◽  
Ofdm System ◽  
Shift Frequency

A novel approach to estimating the Doppler shift frequency from quadrature mixer output

2017 ◽  
Vol 88 (7) ◽  
pp. 073503 ◽  
Author(s):  
M. Y. Wang ◽  
A. D. Liu ◽  
C. Zhou ◽  
J. Q. Hu ◽  
H. Li ◽  
...  
Keyword(s):  
Doppler Shift ◽  
Novel Approach ◽  
Shift Frequency

scholarly journals New Solution for Reducing Doppler Shift in the MB-OFDM System Over High Mobility Multipath Channel for V&I Communication

2015 ◽  
Vol 12 (3) ◽  
pp. 166-173
Author(s):  
Sanaa Kabil ◽  
Raja Elassali ◽  
Fouzia Elbahhar ◽  
Brahim Ait Essaid ◽  
Abdellah Ait Ouahman
Keyword(s):  
Doppler Shift ◽  
High Mobility ◽  
Multipath Channel ◽  
Ofdm System

Shear-Layer Detection in Poststenotic Flow by Spectrum Analysis of Doppler Signals

1988 ◽  
Vol 110 (4) ◽  
pp. 320-325 ◽  
Author(s):  
T. Tamura ◽  
A. Fronek
Keyword(s):  
Shear Layer ◽  
Spectrum Analysis ◽  
Doppler Shift ◽  
Continuous Wave ◽  
Reverse Flow ◽  
Separated Flow ◽  
Sample Volume ◽  
Doppler Spectrum ◽  
Doppler Signals ◽  
Shift Frequency

Spectrum analysis of the Doppler signals was performed 0.5 tube diameters downstream from an axisymmetric constriction with an area reduction of 80 percent in steady flow at a jet Reynolds number of 2840. Both pulsed and continuous wave (CW) Doppler spectra showed significant reverse flow components in the separated flow. The pulsed Doppler spectra exhibited sudden changes when the sample volume crossed the shear layer between the center jet and the separated flow. A power spectrum equation was theoretically derived from continuity of flow to define the Doppler shift frequency for the shear layer velocity. The CW Doppler spectrum showed a minimum spectrum density at a frequency which equalled the shear layer Doppler shift frequency derived from the equation. The pulsed spectra exhibited the sudden changes at the same frequency as well.

Precision Force Measurement Using the Levitation Mass Method (LMM)

2011 ◽  
Vol 103 ◽  
pp. 1-8
Author(s):  
Yusaku Fujii ◽  
Akihiro Takita ◽  
Jakrapong Kaewkhao ◽  
Mitra Djamal ◽  
Takao Yamaguchi
Keyword(s):  
Laser Beam ◽  
Doppler Shift ◽  
Measurement Method ◽  
Force Measurement ◽  
Inertial Force ◽  
High Accuracy ◽  
Optical Interferometer ◽  
Future Prospects ◽  
Mechanical Measurement ◽  
Shift Frequency

This paper reviews the present status and future prospects of the levitation mass method (LMM), which is a precision mechanical measurement method. The LMM has been proposed and improved by the author for 10 years. The force generated by the actuator is measured as the inertial force of the mass levitated with sufficiently small friction using an aerostatic linear bearing and connected to the moving part of the actuator. During the measurement, the Doppler shift frequency of the laser beam reflected by the mass is measured with a high accuracy with the help of an optical interferometer. Subsequently, the velocity, position, acceleration, and inertial force of the mass are calculated using based on this frequency. Simultaneously, the current and voltage supplied to the actuator are measured.

scholarly journals Real-Time Mitigation of the Mobility Effect for IEEE 802.15.4g SUN MR-OFDM

2019 ◽  
Vol 9 (16) ◽  
pp. 3289 ◽  
Author(s):  
Huy Nguyen ◽  
Nam Tuan Le ◽  
Nguyen Cong Hoan ◽  
Yeong Min Jang
Keyword(s):  
Low Power ◽  
Real Time ◽  
Doppler Shift ◽  
Orthogonal Frequency Division Multiplexing ◽  
Cyclic Prefix ◽  
Wide Area ◽  
Wide Area Networks ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System

In order to develop wireless sensor networks, which are defined by the IEEE 802.15.4 specification, researchers are considering low-power wide-area networks (LPWAN) due to their advantages of being long range, low power, low cost, and highly mobile. The issue of mobility is covered in the IEEE 802.15.4g standard for supporting a smart utility network (SUN), which is mainly controlled by orthogonal frequency-division multiplexing (OFDM) modulation. In a high mobility scenario, inter-carrier interference is a primary factor in reducing the performance of OFDM transmissions due to the destruction of the subcarrier component’s orthogonality. This paper analyzes the mobility effect in multi-rate multi-regional orthogonal frequency-division multiplexing (MR-OFDM) for low-power wide-area networks in general, and the SUN MR-OFDM system in particular. As mentioned in standard 802.15.4 2015, IEEE 802.15.4g MR-OFDM is one of the low-power wide-area (LPWA) technologies in which energy optimization problems are of first priority. We are especially interested in simple technologies that provide high efficiency. Therefore, we propose a highly adaptive method that uses the cyclic prefix to mitigate the mobility effect in real time. At a symbol frames interval of 120 us, the Doppler shift effect from the mobility of the MR-OFDM system adapted smoothly. This is not the best method to mitigate Doppler shift but it is a simple method that suits the LPWA network. The proposed scheme clearly simulated the mobility of the MR-OFDM system, and had the advantage of using a cyclic-prefix with a bit error rate performance through Additive White Gaussian Noise (AWGN) and the Rician channel of Matlab.

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